Don't write off major pentatonic either though, I used it like twice before I stumbled onto the arpeggio from Aerodynamic (by Daft Punk). That was neat. When in doubt, Cmaj is easy to work in, just get rid of that third and throw in a 7th or a 9th and it can get interesting pretty quick.

I may be wrong, but much of what I recall passing as acid sounds a lot like Cm with ostinatos based on whole octave shifts. Following this simple approach I generally get fairly convincing acid basslines.